1. Field of the Invention
Aspects of the present invention relate to a rechargeable battery, and more particularly, to a rechargeable battery having the function of detecting water contact.
2. Description of the Related Art
Portable electrical/electronic devices that are compact and light, such as cellular phones, notebook computers, camcorders and the like, have been developed and are currently produced. Battery packs are embedded in such portable electrical/electronic devices, so that the portable electrical/electronic devices can operate in places where a separate power source is not provided. For economy, battery packs generally use rechargeable batteries. Representative examples of rechargeable batteries are nickel-cadmium (Ni—Cd) batteries, nickel-metal hydride (Ni-MH) batteries, lithium (Li) batteries, lithium-ion (Li-ion) rechargeable batteries and the like. In particular, lithium-ion (Li-ion) rechargeable batteries have an operating voltage three times higher than nickel-cadmium (Ni—Cd) batteries or nickel-metal hydride (Ni-MH) batteries, which are widely used as a power source of portable electronic devices. Lithium-ion (Li-ion) rechargeable batteries are also widely used since their energy density per unit weight is higher than those for the other batteries.
Lithium-ion (Li-ion) rechargeable batteries generally use lithium-based oxides as positive electrode active materials and carbon materials as negative electrode active materials. Batteries are generally classified into liquid electrolyte batteries and polymer electrolyte batteries according to the type of electrolyte. Lithium-ion (Li-ion) rechargeable batteries use a liquid electrolyte, and lithium polymer batteries use a polymer electrolyte. Lithium-ion (Li-ion) rechargeable batteries are manufactured into various types of shapes. Representative examples thereof are cylinder type lithium-ion (Li-ion) rechargeable batteries, prismatic type lithium-ion (Li-ion) rechargeable batteries, and pouch type lithium-ion (Li-ion) rechargeable batteries.
Rechargeable batteries having the above shapes in a bare cell state are incorporated into a battery pack that also includes protective circuit modules, exterior finishing materials and the like. Protective circuit modules control charging/discharging when rechargeable batteries are charged/discharged, and block current flow from charging/discharging when the rechargeable batteries are over-heated or over-charged.
Devices such as labels for detecting water contact are separately attached to battery packs and detect whether the battery packs contact water. However, labels for detecting water contact need to be separately, often manually attached to the battery packs, which reduces the efficiency of producing finished battery packs.